Boiler-plug.



C. L. MoVOY.

BOILER PLUG.

i AAAAAAAAA o1; FFFFFF AR. 55555 9.y 944,205. x Patented De@.21,1909.

l To all whom it may comem:

Umransrxras PATENT orricn CHARLES L. McVOY, OF PENSACOLA, FLORIDA.

BOILER-PLUG.

Be it known that I, CHARLES L. McVoY, a citizen of the United States, residing at Pensacola, in the county of Escambia and State of Florida, have invented new and useful Improvements in Boiler-Plugs, of which the following is a specification. l

This invention is an improved fusible plug for steam boilers to protect steam boilers from overheating.

One object of my invention is to effect improvements in the construction of the plug whereby when the fusible core is melted water is prevented from escaping from the boiler.

A further object of the invention is to effect improvements in the construction of the plug whereby the fusible core is prevented from being blown out by pressure.

A' further object is to combine with a plug having a fusible core, a whistle or other signaling device which is operated when the core becomes. fused in the plug, so as to sound an alarm.

The invention consists'in the construction, combination and arrangement of devices hereinafter described and claimed. l In the accompanying drawings z-Figure 1 is a cross sectional view of a portion of a steam boiler provided with a fusible plug and an alarm whistle arranged and constructed in accordance with. my invention. Fig. 2 is a detail vertical central sectional view of the plug. Fig. 3 is a detail horizontal sectional view of the same on the plane indicated by the line a-a of Fig. 2. Fig. 4 is a detail sectional view illustrating la modied construction of the plug. Fig. 5 is a horizontal sectional view of the same on the plane indicated by the line b-b of Fig. 4.

ln the boiler here shown which is of the usual type employed on steam ships, the shell is indicated at 1, the lire box at 2 and the crown or table sheet at 3. The crown or v,table sheet is provided with a screw threaded opening 4 which extends entirely therethrough to receive the screw threaded portion 5 of the shell 6 of my improved plug. The said shell is preferably made of brass, but may be made of any other suitable comparatively refractory metal, fusible only at a comparatively high temperature. The said plug shell is provided with a centrallydisposed, downwardly-ta ering bore 7 which terminates short of the Bottom of the plug by a wrench for ing 12, the said pipe tirely Specification of Letters Patent. Patented Dec. 21;, 1909. Application led Marchi, 1909. Serial No. 481,272.

shell so that the bottom. of they plug shell orI that portion thereof which is exposed to the fire is entirely closed under all conditions as at 8. An annular channel 9 is formed in the plug shell extending around and communicating with the downwardly-tapering bore thereof, and at a suitable bottom of the said plug shell are a suitable number yof radially disposed spill openin rs l() of which three are lhere shown. It will lie observed that the said spill openings are disposed slightly above that portion of the plug which is screwed in the opening 4 in the crown or table sheet of the boiler so that the said spill o enings are entirely above said crown or ta le sheet. Moreover it will be observed that the upper portion of the plug shell extends considerably above the table sheet and into the water space o f the boiler so that itis removed from the greater heat of the crown sheet and subject to comparatively uniform temperature.

In the form ofv the plug shown. ln Figs. 2 and 3 the lupper end of the plug shell has a polygonal head 11 adapted to be engaged removing the plug shell. The plug shell is also provided with a threaded opening 12 which communicates with the downwardlytapering bore 7 and is disposed above the crown or of the boiler and a pipe 13 of suitable size distance from the the purpose of applying ork table sheet and in the water spacel y.

has its lower end screwed into the said openup through the top of the boiler and being provided above the boiler with a whistle or other suitable alarm-sounding device 14, a ball valve 15 below the Whistle and an unvalved arm 16 which carries a ga e 17.

'The bore of the plug shell is filed with a fusible core 18 which extends into the channel 9 to form an annular flange or shoulder 19 whichrmly secures the core in the lug shell so that vthe said core cannot be b own out by pressure. The fusible, core when cast in the plug lshell also forms arms 20 in the spill openings 10 serve to secure the fusible core so securely in the plug shell that lsaid core cannot be blown out from the bore of the shell.

Since the bottom of the plug shell is en closed the fusible core is protected from the direct heat of the fire box and of the crown or table sheet and since the plug extends considerably into the water space extending verticallyY and Said arms also ilo i of the boiler above the crown sheet there isv no danger of premature' or unnecessary fusing of thel fusible core. In the event howvever that a dangerous temperature is attained the fusible core fuses and runs .out

through t-he spill openings into the 'Water space of the boiler above -the 'crown or table lsheet thus exposing and opening the lower inner end of the pine 13 with the result 4that when the core is fused and hence the waterl is prevented from escaping or being forced from the boiler through the plug shell when the coreis fused Moreover itwill be understood that "my improved fusible plug owing to its constructionrand arrangement with reference to the crown or table sheet is comparatively accessible and it is comparatively easy to replace the fusible core. In the form of my invention shown in Fig. 4 the polygonal head 21 of the plug shell is at the lower end thereof -Where it will extend into the fire box.

While my i-mprovedfusible plug' 1s. here shown applied to a marine boiler it w1ll be understood that it may be used also in boilers of other types.

Having thus described the invention what `is claimed as new ifs K A plug shell to be litted iny an opening of the crown lsheet of a steamv boiler with the upper portion of said plug, shell extending into the waterspace of the boiler, said plug shell having a bore extending downwardly.

from its upper end and terminating short ofI its lower end and provided with a spill opening extending from said boreto' one side. of the plug shell at a point above the crown sheet, a uid pressure operated signaling device, a pipe connected to the plug shell ata point on one side of the latter and also connected to said 4signaling device and a fusible core in the bore of the plug shell normally closing the inlet end of said pipe.

In testimon whereof I aflix my signa-ture in presence o two witnesses.

' CHARLES L. MCVOY. Witnesses:

I-I. G. WHITE, S. J.'GOURDLER. 

